Update July 15 2014: The paper has been published! You may be able to get a free download here. The paper is Guillaume Mauger, Yoram Bauman, Tamilee Nennich, and Eric Salathé, “Impacts of Climate Change on Milk Production in the United States”, The Professional Geographer, DOI: 10.1080/00330124.2014.921017 (2014). Abstract: Climate change is likely to affect milk production because of the sensitivity of dairy cows to excessive temperature and humidity. We use downscaled climate data and county-level dairy industry data to estimate milk production losses for Holstein dairy cows in the conterminous United States. On a national level, we estimate present-day production losses of 1.9 percent relative to baseline production and project that climate impacts could increase these losses to 6.3 percent by the end of the twenty-first century. Using present-day prices, this corresponds to annual losses of $670 million per year today, rising to $2.2 billion per year by the end of the century. We also find that there is significant geographic variation in production losses and that regions currently experiencing the greatest heat-related impacts are also projected to experience the greatest additional losses with climate change. Specifically, statewide average estimates of end-of-century losses range from 0.4 percent in Washington to a 25 percent loss in annual milk production in Florida. Given that the majority of these losses occur in the summer months, this has the potential to significantly impact operations in hotter climates.
Here’s a draft of “Impacts of Climate Change on Milk Production in the United States”, a new paper I’ve worked on with Eric P Salathé Jr and Guillaume S Mauger of UW and Tamilee D Nennich of Purdue. Note that this is a working paper that has not yet been published.
Abstract: Climate change is likely to affect milk production because of the sensitivity of dairy cows to excessive temperature and humidity. We use downscaled climate data and county-level dairy industry data to estimate Holstein milk production losses in the conterminous United States. We find that there is significant geographic variation in production losses and that regions currently experiencing the greatest heat-related impacts are also projected to experience the greatest additional losses with climate change. On a national level, we project that climate impacts could reduce end-of-century milk production per cow by 6.3% relative to baseline production.
Feedback welcome! And FYI we also have a spreadsheet with county-level data that we’ll make available at some point (probably after publication) but is probably available upon request.
PS. Some acknowledgments: The authors acknowledge the skilled assistance of Robert Norheim in providing GIS analysis and maps used in this paper and of Hye Jin (Jenny) Chang in gathering dairy industry data. This research was supported in part by the Climate Impacts Group of the Joint Institute for the Study of the Atmosphere and Ocean under NOAA Cooperative Agreement No. NA17RJ1232.
PPS. Thanks to an article about our paper by the UW News and Information’s Nancy Gohring (“Got milk? Climate change means stressed cows in southern U.S. may have less”, July 11, 2012), we’ve gotten a bit of press (see below), of which the most hilarious is undoubtedly “Washington College Students Rally to Protect Cows From Global Warming”, which attributes the research to “University of Washington economist Rainbow Moonglow Rabinowitz.”